As a secondary battery used in an electric vehicle and a mobile device, a nickel-metal hydride secondary battery is often mounted. Recently, a lithium-ion battery has been developed as a secondary battery that can be increased in output and capacity and is at the stage of start of practical use.
The lithium-ion battery is made by using a metal double oxide containing lithium for a cathode and a material that can receive and release lithium such as carbon for an anode, and impregnating it with an electrolytic solution composed of a lithium salt capable of dissociating into ions and an organic solvent capable of dissolving the lithium salt (refer to Patent Document 1 and so on).
From the need to increase the safety of the battery at wrong use because the electrolytic solution is liquid and therefore may leak and an inflammable material is used, an all-solid lithium secondary battery using a solid electrolyte in place of the electrolytic solution is also disclosed (refer to Patent Document 2 and so on).
The lithium-ion battery is expensive in cost because of use of lithium being a rare metal, and therefore a secondary battery with higher performance and larger capacity is required also in terms of performance.
Under such a situation, the present inventors suggest an all-solid type semiconductor battery (hereinafter, referred to as a quantum battery) capable of reduction in cost and safe operation with a simple configuration (PCT/JP 2010-067643).
The quantum battery is constituted by stacking a substrate, a conductive base electrode, a charge layer having an n-type metal oxide semiconductor covered with an insulating material and undergone a photoexcitation structural change to form an energy level in a band gap so as to trap electrons, a P-type semiconductor layer, and a conductive counter electrode. A power supply is connected between the base electrode and the counter electrode to charge the charge layer.
For the quantum battery, current-voltage characteristics and charge/discharge characteristics are evaluated for confirming the function in its production process.
The current-voltage characteristics are generally known as a method of evaluating the characteristics of a semiconductor and is applied to performance evaluation also for the secondary battery.
For example, there is a method of detecting the internal resistance on the basis of the measurement values of the voltage and the current at the time of discharging and the time of charging a hybrid vehicle battery, and estimating accurate current-voltage characteristics of the battery to detect more accurate internal resistance of the battery (refer to Patent Document 3 and so on). There is another method of dividing an output range of a battery into a plurality of regions, measuring a predetermined number of sets of voltage and current for each of the regions, specifying the current-voltage characteristics of the battery on the basis of the measurement values, and calculating the maximum output of the battery on the basis of the current-voltage characteristics (refer to Patent Document 4 and so on).
Further, for producing the quantum battery, the performance as the secondary battery depends on the charge layer, and therefore more efficient production is possible by evaluating the charge layer in the middle where the charge layer is stacked in the production process than by evaluating the charge layer in a complete product.
Evaluation of the function in the middle of the production process is means performed in a field of the semiconductor. For example, there is a measuring device in which a measuring source electrode and a measuring drain electrode are provided exposed on both sides of a measuring gate electrode covered with an insulating film for the purpose of directly measuring the electric characteristics of the semiconductor being an active layer of a field effect thin film transistor without actually creating it.
When the exposed surfaces of the measuring source electrode, the measuring drain electrode, and the insulating film between them are brought into contact with the surface of the semiconductor, the contact portion constitutes a coplanar-type pseudo electric field effect thin film transistor. This enables, before creation of an element, measurement similar to that in the case of the normal coplanar-type pseudo electric field effect thin film transistor after creation of the element (refer to Patent Document 5 and so on).
There also is a method of accurately measuring the current-voltage characteristics when evaluating an SOI substrate using a pseudo MOSFET and suppressing the influence by temporal change to the minimum to thereby obtain a value with good reproducibility (refer to Patent Document 6 and so on), and a semiconductor probe for measurement (refer to Patent Document 7 and so on) is also suggested.